Loss Of Imprinting Of IGF2 Gene A Hereditary Risk Factor For Colon Cancer

NEW YORK (Reuters Health) - Abnormal imprinting of the insulin-like growth factor II gene (IGF2) appears to be a hereditary -- not environmental --risk factor for colorectal neoplasia.

A multicenter team led by Dr. Marcia Cruz-Correa at the Johns Hopkins University School of Medicine in Baltimore, Maryland explains in the April issue of Gastroenterology that genomic imprinting normally silences the maternally inherited copy of the gene for insulin growth factor II. Loss of imprinting has been associated with individual and family histories of colorectal cancer.

The researchers sought to determine whether loss of imprinting of the IGF2 gene is associated with environment risk factors for colorectal cancer, including exposure to tobacco or alcohol, consumption of specific nutrients, and use of nonsteroidal anti-inflammatory drugs.

The prevalence of loss of imprinting in peripheral blood lymphocytes was analyzed in 172 subjects, 65 of whom had colorectal neoplasias.

"Persons with colorectal neoplasia (adenomas/cancer) had a 5.1-fold...increased risk of having loss of imprinting of IGF2" compared to normal subjects, the investigators found. On the other hand, there was no association between loss of imprinting and any of the environmental exposures.

In an accompanying editorial, Dr. Randy L. Jirtle of Duke University Medical Center in Durham, North Carolina writes that the findings of Dr. Cruz-Correa and her colleagues "provide compelling support for the postulate that abnormal IGF2 imprinting in peripheral blood lymphocytes is not environmentally acquired during adulthood, but rather occurs early in embryonic development."

Dr. Jirtle adds, "Consequently, detection of this epigenetic perturbation could possibly be performed early in life allowing for cancer-preventive measures to be started before the early stages of colorectal neoplasia are first visually evident."

Source: Gastroenterology 2004;126:964-970 [ Google search on this article ]

MeSH Headings: Colonic Diseases : Digestive System Neoplasms : Gastrointestinal Neoplasms : Insulin-Like Growth Factor II : Intestinal Neoplasms : Neoplasms : Neoplasms by Site : Colorectal Neoplasms : Genomic Imprinting : Diseases

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